World Journal of Nuclear Medicine最新文献

The Northern Territory (NT) of Australia is a large, low-density territory with the highest percentage of First Nations people in Australia, many of whom live remotely and encounter difficulties and barriers to accessing services. This determines significant gap in healthcare delivery inclusive of Nuclear Medicine and theranostic therapy services. In particular, no theranostic service for cancer patients is currently available in the NT. A narrative retrospective analysis of the provision of nuclear medicine services within the NT at the Royal Darwin Hospital was undertaken to determine the suitability and relevance of the establishment of a new theranostic service within the NT, catered to the specific needs of the local population and in particular of the large proportion of First Nations Patients that are likely to benefit from the local service. Building on the preexisting structure of Nuclear Medicine and PET, inclusive of a comprehensive facility with local production of radiopharmaceuticals, it is expected that the implementation of a theranostic service within the NT will have a high intake and a flow-down positive effect on cancer care within the NT. The implementation of cultural safety principles within the department is embedded in our model of service provision and will further be implemented in the theranostic service delivery. A theranostic service within the NT will prove beneficial to the NT population and sustainable financially. Principles of Cultural safety are paramount to service provision in the NT, and will hopefully contribute to enhancing the experience and improving the outcomes for First Nations patients.

Objective: ⁶⁸ Ga-PSMA-HBED-CC ( ⁶⁸ Ga-PSMA-11) was approved by the U.S. Food and Drug Administration as the first prostate-specific membrane antigen (PSMA)-targeted positron emission tomography (PET) imaging drug for patients with prostate cancer. However, the utility of ⁶⁸ Ga-PSMA-HBED-CC may be limited due to PET/CT or PET/MR accessibility and ⁶⁸ GaCl ₃ availability produced from ⁶⁸ Ge/ ⁶⁸ Ga generator or cyclotron. Thus, in-house preparation of ^99m Tc-PSMA-HBED-CC was developed as an alternative to ⁶⁸ Ga-PSMA-HBED-CC to be ubiquitous and affordable in the worldwide population.

Methods: A solution of ^99m Tc-pertechnetate was added to PSMA-HBED-CC and 4% SnCl ₂ ·2H ₂ O in a 10-mL sterile vial. The mixture was heated at 100°C for 15 minutes and then allowed to cool to room temperature. Labeling conditions were optimized to maximize the radiochemical yield of ^99m Tc-PSMA-HBED-CC. The chelation completeness was monitored using instant thin layer chromatography, and the stability of ^99m Tc-PSMA-HBED-CC was subsequently evaluated.

Results: The radiolabeling of ^99m Tc-PSMA-HBED-CC was successful using the appropriate amount of 10 µg PSMA-HBED-CC 3 µg SnCl ₂ ·2H ₂ O and ^99m Tc-pertechnetate 370 MBq at 100°C for 15 minutes, yielded the best result in high radiochemical yield (71.49 ± 2.42%), radiochemical purity (98.29 ± 2.65%), and specific activity of 37.84 ± 1.47 GBq/µmol. ^99m Tc-PSMA-HBED-CC is stable with radiochemical purity of more than 95% within 4 hours at room temperature.

Conclusion: A new labeling method of ^99m Tc-PSMA-HBED-CC was developed. Quality control parameters of ^99m Tc-PSMA-HBED-CC met the criteria in accordance with the European Pharmacopoeia.

The use of radionuclides for targeted radiopharmaceutical therapy (RPT) is a rapidly evolving field in nuclear medicine and oncology. With the integration of imaging and therapy, therapeutic nuclear medicine has made remarkable progress in recent years. One particularly promising area of research is the use of α-emitting radionuclides, which possess unique physical properties that provide notable advantages, including the ability to target single tumor cells with high precision. Although the only targeted α therapy (TAT) currently approved by the United States Food and Drug Administration is ²²³ Ra-dichloride for the treatment of castration-resistant prostate cancer with skeletal metastases, a search on clinicaltrials.gov yields a significant number of early- and late-stage clinical trials utilizing 223-Ra, 225-Ac, 211-At, 212-Pb, and 227-Th are in progress, indicating that more TATs are on the horizon. As the prevalence of use for TAT increases, it is important to consider the logistics of TAT administration and the requirements for radiation safety and patient discharge. This review aims to provide a comprehensive overview of the advancements, relevant clinical trials, and logistical considerations associated with targeted α RPT in oncology.

The case presents a 57-year-old male with metastatic papillary thyroid carcinoma (PTC) to the lymph nodes, lung, and mediastinum. Despite receiving multiple high-dose radioactive iodine (RAI) therapies, the patient's serum thyroglobulin levels continued to rise. The patient, who was unresponsive to RAI therapy, was being evaluated for suitability for ¹⁷⁷ Lu-DOTATATE therapy. Therefore, after the third high-dose treatment, simultaneous ⁶⁸ Ga-DOTATATE PET/MRI and ¹⁸ F FDG PET/CT imaging were performed, revealing a painless mass in the left gluteal region. The gluteal mass was excised, and histopathology confirmed it as metastatic PTC. Muscle metastases are extremely rare for PTC. This case exemplifies the different levels of tumoral affinity shown by aggressive variants of PTC across three distinct imaging modalities: ⁶⁸ Ga-DOTATATE PET/MRI, ¹⁸ F FDG PET/CT, and whole-body iodine scintigraphy.

Melioidosis is an infectious disease that is caused by a gram-negative bacillus, Burkholderia pseudomallei , which has been designated as a category B bioterrorism agent by the U.S. Centers for Disease Control and Prevention. Melioidosis manifests as a multi-system disorder. The effectiveness of ¹⁸ F-FDG PET/CT (18-fluorine-fluorodeoxyglucose positron emission tomography-computed tomography) in diagnosing or managing melioidosis is currently uncertain or not well-established. ¹⁸ F-FDG PET/CT is a useful tool in detecting the location and extent of abscess formation, assessing the organs involved, and detecting occult foci of infection, due to the multifocal nature of the disease. Herein, we present cases of two patients referred for a whole-body ¹⁸ F-FDG PET/CT scan with a history of pyrexia of unknown origin.

Pediatric bronchial carcinoid tumors are rare, accounting for a significant proportion of primary lung tumors in children but only a small fraction in adults. These tumors can present with symptoms such as cushing's syndrome due to ACTH secretion. Complete surgical resection typically results in favorable outcomes, with most tumors expressing somatostatin receptors, making them amenable to peptide receptor radionuclide therapy (PRRT) with (177Lu)Lu-DOTA-TATE (LuTATE). This case report describes a 13-year-old female with a bronchial carcinoid tumor treated with multi-cycle high-dose LuTATE therapy in the neoadjuvant setting. Initial imaging and biopsy confirmed a grade G1 pulmonary carcinoid with intense somatostatin receptor expression. The patient underwent two cycles of LuTATE, with dosimetry calculations guiding dose escalation while maintaining safe kidney radiation exposure. Posttherapy scans showed a significant metabolic response of suspected nodal metastases and evidence of partial response of the primary tumor. Two further LuTATE cycles were administered, with continued monitoring of kidney dosimetry to ensure safety. The treatment was well-tolerated, and the patient showed no significant complications. The case highlights the potential of LuTATE therapy to downstage tumors and reduce surgical morbidity in pediatric patients. Given the rarity of pediatric bronchial carcinoid tumors, phase III clinical trials are unlikely, but this report supports the inclusion of LuTATE in multidisciplinary treatment planning. In conclusion, LuTATE therapy, guided by dosimetry calculations, offers a valid treatment option for pediatric bronchial carcinoid tumors, balancing efficacy, and safety in a challenging clinical scenario.

Radioembolizaton of hepatic malignancy is an accepted palliative treatment option in many subjects. The process of working up an individual for a radioembolization procedure permits pretreatment radiation dosimetry to be estimated, which is not possible with many other theranostic pairs of radionuclides. These estimates can then be used to prescribe the desired amount of radionuclide therapy (RNT), in radiation dose units of gray (Gy), to treat the cancer tissues to a desired level as well as permitting the radiation dose to the normal liver compartment to be minimized. As such, radioembolization represents an excellent example of a theranostic approach to treatment where individualization of the therapy can be highly tailored. The necessary tools are now available to implement this approach on a wider scale, which should improve outcomes for the treated individuals. The aim of this review article was to present a contemporary approach to personalized treatment planning for radioembolization and to emphasize the theranostic aspects of the process. A clinical case is presented demonstrating the potential for excellent clinical outcomes using an image-based and informed treatment plan developed by the multidisciplinary team of nuclear physicians, interventional radiologists, medical oncologists, and medical physicists.

Introduction: The coexistence of multiple malignancies presents diagnostic and therapeutic challenges. Breast and thyroid cancers are among the most frequently diagnosed malignancies in women, and studies suggest a potential bidirectional association. While fluorodeoxyglucose (FDG)-positron emission tomography (PET)/computed tomography (CT) is a valuable imaging modality for evaluating breast cancer, its sensitivity in detecting low-metabolic subtypes remains limited. Additionally, incidental FDG-avid thyroid lesions require further evaluation due to their potential malignancy risk.

Case report: We present a 61-year-old female with a suspected left breast malignancy, suggestive of luminal A subtype, showing low FDG uptake (maximum standardized uptake value [SUVmax] 2.0) on PET/CT, despite mammographic and ultrasound findings suggestive of malignancy (Breast Imaging-Reporting and Data System 4A and V). Additionally, an incidental left thyroid lesion (4.0 × 3.8 cm, SUVmax 3.4) with calcifications was detected, raising suspicion for malignancy. The discordant imaging findings in this case highlight the limitations of FDG-PET/CT and emphasize the necessity of multimodal imaging and histopathological confirmation.

Conclusion: This case underscores the importance of integrating multiple imaging modalities for accurate diagnosis. While PET/CT is useful for systemic staging, its limitations in detecting certain breast cancer subtypes necessitate complementary imaging techniques and histopathological confirmation. The incidental thyroid lesion also required further assessment, reinforcing the need for a comprehensive diagnostic approach.

We present the first described case of retroperitoneal metastasis from follicular thyroid carcinoma (FTC). This was incidentally discovered as a PSMA (prostate-specific membrane antigen)-positive lesion on PSMA-positron emission tomography (PET)-computed tomography (CT) in a patient with synchronous prostate cancer (PCa).The expanding utilization of PSMA-PET-CT has revealed tracer uptake in several nonprostatic conditions. A 68-year-old man investigated for PCa, underwent magnetic resonance imaging, which revealed an 18-mm retroperitoneal soft tissue nodule lateral to the left psoas and a left pelvic node. PSMA-PET-CT showed tracer uptake in the primary PCa, retroperitoneal lesion, and pelvic node with an incidental high-grade focus in the thyroid. A CT following a period of androgen deprivation demonstrated no response in the retroperitoneal lesion, while the pelvic node became smaller. Fine-needle aspiration (FNA) of the thyroid was performed, although an ultrasound was initially reported as benign. FNA cytology (FNAC) was interpreted as a benign nodule. However, CT-guided biopsy of the retroperitoneal lesion revealed follicular thyroid tissue. The differential diagnoses were ectopic thyroid tissue and FTC. FNAC and ultrasound were reviewed at the thyroid multidisciplinary meeting (MDM) and upgraded to follicular atypia and suspicious for malignancy, respectively. Left hemithyroidectomy confirmed an angioinvasive follicular carcinoma. Completion thyroidectomy revealed a small incidental micropapillary carcinoma. Single photon emission computed tomography (SPECT)-CT post- ¹³¹ I treatment showed intensely iodine-avid tissue within the thyroid bed and retroperitoneal deposit. On follow-up ¹²³ I-SPECT-CTs, there was no abnormal iodine uptake and the retroperitoneal deposit decreased from 18 to 5 mm, presumed as scar tissue. Thyroglobulin reduced from 7.7 to < 0.1 ug/L. MDM recommended 6 monthly surveillance. PSMA-positive lesion evaluation can be challenging due to PSMA expression in nonprostatic conditions. As illustrated by this case, unusual distribution of tracer uptake requires further investigations and a multidisciplinary approach to guide management. High PSMA expression in differentiated thyroid cancer was associated with shorter progression-free survival and may be considered a marker of aggressiveness. Such tumors could be candidates for targeted PSMA-radioligand therapy (e.g., ¹⁷⁷ lutetium), particularly in radioiodine-negative/refractory cases, which are difficult to treat.